[#LU-13119] lustre-initialization crashed in common_file

LDISKFS-fs (dm-4): mounted filesystem with ordered data mode. Opts: user_xattr,errors=remount-ro,no_mbcache,nodelalloc BUG: unable to handle kernel NULL pointer dereference at 0000000000000078 IP: [<ffffffff812d5995>] common_file_perm+0x15/0x180 Oops: 0000 [#1] SMP Supported: No, Unsupported modules are loaded CPU: 0 PID: 2995 Comm: mount.lustre Tainted: 4.4.180-94.100_lustre Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 Call Trace: security_file_permission+0x3e/0xc0 iterate_dir+0x32/0x110 osd_ios_general_scan+0x12e/0x250 [osd_ldiskfs] osd_initial_OI_scrub+0x5e/0xc00 [osd_ldiskfs] osd_scrub_setup+0x8f5/0x960 [osd_ldiskfs] osd_device_alloc+0x5ac/0x8c0 [osd_ldiskfs] obd_setup+0xb8/0x230 [obdclass] class_setup+0x468/0x7c0 [obdclass] class_process_config+0x1890/0x27b0 [obdclass] do_lcfg+0x235/0x490 [obdclass] lustre_start_simple+0x85/0x1f0 [obdclass] server_fill_super+0xe81/0x1640 [obdclass] lustre_fill_super+0x436/0x8d0 [obdclass] mount_nodev+0x48/0xa0 mount_fs+0x3a/0x170 vfs_kern_mount+0x62/0x110 do_mount+0x213/0xcd0 SyS_mount+0x85/0xd0

It seems that the SLES kernel is trying to apply AppArmor security policies to the Lustre filesystem (not sure why, since we , since common_file_perm() only exists in security/apparmor/lsm.c:

static int common_file_perm(int op, struct file *file, u32 mask)
{
        struct aa_file_cxt *fcxt = file->f_security;
        struct aa_profile *profile, *fprofile = aa_cred_profile(file->f_cred);
        int error = 0;

        BUG_ON(!fprofile);

        if (!file->f_path.mnt ||
            !mediated_filesystem(file->f_path.dentry))
                return 0;

        profile = __aa_current_profile();

        /* revalidate access, if task is unconfined, or the cached cred
         * doesn't match or if the request is for more permissions than
         * was granted.
         *
         * Note: the test for !unconfined(fprofile) is to handle file
         *       delegation from unconfined tasks
         */
        if (!unconfined(profile) && !unconfined(fprofile) &&
            ((fprofile != profile) || (mask & ~fcxt->allow)))
                error = aa_file_perm(op, profile, file, mask);

        return error;
}


static int apparmor_file_permission(struct file *file, int mask)
{
        return common_file_perm(OP_FPERM, file, mask);
}

int iterate_dir(struct file *file, struct dir_context *ctx)
{               
        struct inode *inode = file_inode(file);
        bool shared = false;
        int res = -ENOTDIR;
        if (file->f_op->iterate_shared)
                shared = true;
        else if (!file->f_op->iterate)
                goto out;

        res = security_file_permission(file, MAY_READ);
        :
        :
}

osd_ios_general_scan(struct osd_thread_info *info, struct osd_device *dev,
                     struct dentry *dentry, filldir_t filldir)
{
        struct file                  *filp  = &info->oti_file;
        struct inode                 *inode = dentry->d_inode;
        const struct file_operations *fops  = inode->i_fop;

        filp->f_pos = 0;
        filp->f_path.dentry = dentry;
        filp->f_flags |= O_NOATIME;
        filp->f_mode = FMODE_64BITHASH | FMODE_NONOTIFY;
        filp->f_mapping = inode->i_mapping;
        filp->f_op = fops;
        filp->private_data = NULL;
        set_file_inode(filp, inode);
        rc = osd_security_file_alloc(filp);
        if (rc)
                RETURN(rc);        do {
                buf.oifb_items = 0;
                rc = iterate_dir(filp, &buf.ctx);
        } while (rc >= 0 && buf.oifb_items > 0 &&

[LU-13119] lustre-initialization crashed in common_file_perm() on SLES12 Created: 09/Jan/20 Updated: 23/Jan/20 Resolved: 23/Jan/20
Status:	Resolved
Project:	Lustre
Component/s:	None
Affects Version/s:	None
Fix Version/s:	Lustre 2.14.0

[LU-13119] lustre-initialization crashed in common_file_perm() on SLES12 Created: 09/Jan/20 Updated: 23/Jan/20 Resolved: 23/Jan/20